Clean energy has its drawbacks

Tuesday

Apr 8, 2008 at 12:01 AMApr 8, 2008 at 7:00 AM

Clean energy sounds good. Who doesn't want to use energy that will not pollute the planet? Unfortunately, some of the solutions proposed and being implemented produce more pollution or require more energy than the fuels they displace.

Much of the hype about renewable and clean energy is based on politics and emotion rather than science. A cost-benefit study needs to be conducted for any proposed energy source. This involves determining all the costs associated with production of the energy (both energy required and resources used up in the process) and the expected benefits from its use. A study of side effects is also essential. It is educational to look at these effects for the most commonly touted clean energy sources, ethanol and biodiesel.

Ethanol

Ethanol as a replacement for or additive to gasoline is the PC darling of the day. It will decrease the use of crude oil, but at what cost?

The amount of water required to grow the biomass and ferment it to ethanol is excessive for any region with a shortage of water, such as western Kansas. The fermentation process also produces carbon dioxide, classified as a greenhouse gas, suspected of increasing global warming.

Undesired side effects, besides excessive water use in dry areas, are the destruction of rainforests around the world and increased food prices. Those crops used to produce ethanol are not available as food, so more land is needed to grow food crops. Much of this cropland is provided by destroying the rainforests in countries such as Brazil, Malaysia and Indonesia.

The connection between ethanol use and rainforest destruction is not straightforward. If much of the U.S. corn crop is used in ethanol refineries, corn prices increase accordingly. Increased corn prices cause many soybean farmers to convert to planting corn. Lowered soybean production increases its price. Brazilian soybean growers expand into fields formerly used as cattle pasture. The displaced cattlemen then clear new grazing land from the rainforests.

Some figures of interest: The corn needed to fill an ethanol-fueled SUV would feed a person for 365 days; and approximately 750,000 acres of Brazilian rainforest (about the size of Rhode Island) was lost in the last six months of 2007.

Increased food prices means there will be more starving people in the world. Two University of Minnesota researchers predicted in 2004 that the number of people going hungry by 2025 would be 625 million. In 2007, they adjusted their prediction for the increased food costs due to inflation caused by biofuels and predicted 1.2 billion hungry people.

If all the corn grown in the U.S. were fermented to ethanol, it would only displace 20 percent of on-road fuel consumption in the country. The increased price of food and numbers of starving people in the world is a heavy price to pay for the benefits obtained.

The only source of ethanol that will cut emissions by more than it takes to produce the ethanol is sugarcane and possibly sugar beets. I have seen no studies on sugar beets, but suspect the results would be the same. Fermentation of sugar is much more straightforward and requires less energy than that of starches, which are found in corn, switch grass and other carbohydrate sources. They require conversion of the starches into sugar before fermentation can take place.

Biodiesel

Biodiesel is produced from vegetable oils. The process is more direct because fermentation is not required. On the other hand, most vegetable oils are used directly as food or in its preparation. More corn is indirectly used as human food when people eat meat produced by animals eating the corn.

Although less energy is required in the production of biodiesel, and carbon dioxide is not generated in its production, the concerns about food prices and deforestation are the same as those raised by ethanol use.

There is a need for further research on these fuel additives before the headlong dash to alternative fuels leads to irreversible damage to our planet.

More information can be found in the article "The Clean Energy Scam" by Michael Grunwald in the April 7 issue of Time. The Web site of the Energy Information Administration, www.eia.doe.gov, is an excellent source of information in this area.

Delbert Marshall, Hays, is a professor emeritus of chemistry at FHSU, and a member of the Generations Advisory Group.

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